Chelsea and Westminster Hospital, London, United Kingdom.
Institute of Reproductive and Developmental Biology, London, United Kingdom.
PLoS One. 2021 Jun 24;16(6):e0252720. doi: 10.1371/journal.pone.0252720. eCollection 2021.
Previously, we showed that cAMP increased COX-2 expression in myometrial cells via MAPK. Here, we have extended these observations, using primary myometrial cell cultures to show that the cAMP agonist, forskolin, enhances IL-1β-driven COX-2 expression. We then explored the role of A-kinase interacting protein (AKIP1), which modulates the effect of PKA on p65 activation. AKIP1 knockdown reversed the effect of forskolin, such that its addition inhibited IL-1β-induced COX-2 mRNA expression and reduced the IL-1β-induced increase in nuclear levels of p65 and c-jun. Forskolin alone and with IL-1β increased IκBα mRNA expression suggesting that in the context of inflammation and in the presence of AKIP1, cAMP enhances p65 activation. AKIP1 knockdown reversed these changes. Interestingly, AKIP1 knockdown had minimal effect on the ability of forskolin to repress either basal OTR expression or IL-1β-stimulated OTR mRNA expression. AKIP1 was up-regulated by IL-1β, but not stretch and was repressed by cAMP. The mRNA expression of AKIP1 increased in early labour in tandem with an increase in COX-2 mRNA and protein. AKIP1 protein levels were also increased with inflammation and stretch-induced preterm labour. Our results identify a second important cAMP effector-switch occurring at term in human myometrium and suggest that a hitherto unrecognized interaction may exist between AKIP1, NFκB and AP-1. These data add to the proposition that cAMP acts as a key regulator of human myometrial contractility.
先前，我们表明 cAMP 通过 MAPK 增加了子宫肌细胞中的 COX-2 表达。在这里，我们使用原代子宫肌细胞培养物扩展了这些观察结果，表明 cAMP 激动剂佛司可林增强了 IL-1β 驱动的 COX-2 表达。然后，我们探索了 A-激酶相互作用蛋白（AKIP1）的作用，AKIP1 调节 PKA 对 p65 激活的作用。AKIP1 敲低逆转了佛司可林的作用，使得其添加抑制了 IL-1β 诱导的 COX-2 mRNA 表达，并降低了 IL-1β 诱导的核内 p65 和 c-jun 水平增加。佛司可林单独和与 IL-1β 一起增加了 IκBα mRNA 表达，表明在炎症的情况下并且存在 AKIP1 的情况下，cAMP 增强了 p65 的激活。AKIP1 敲低逆转了这些变化。有趣的是，AKIP1 敲低对佛司可林抑制基础 OTR 表达或 IL-1β 刺激的 OTR mRNA 表达的能力几乎没有影响。IL-1β 上调 AKIP1，但拉伸不会，并且 cAMP 会抑制 AKIP1。AKIP1 的 mRNA 表达在早产的早期与 COX-2 mRNA 和蛋白的增加同时增加。AKIP1 蛋白水平也随着炎症和拉伸诱导的早产而增加。我们的结果确定了人子宫肌层在足月时发生的第二个重要的 cAMP 效应开关，并表明 AKIP1、NFκB 和 AP-1 之间可能存在以前未被认识到的相互作用。这些数据增加了 cAMP 作为人子宫肌层收缩性关键调节剂的观点。
